Pediatric Hydronephrosis

Hydronephrosis means that there is more urine in the kidneys and ureters than normal. There are several causes, many of which do not cause any harm to the kidneys, but in some cases hydronephrosis can be associated with poorly functioning kidneys. Hydronephrosis can affect one (unilateral) or both (bilateral) kidneys, and it resolves on its own in about half of all cases.

Hydronephrosis is most often caused by abnormal development of the upper urinary tract. Sometimes it can be caused by blockage at some part of the urinary tract or by reflux of urine (abnormal backflow of urine from the bladder). There are few genetic causes of hydronephrosis and it can occur with other conditions in the baby.

There are three main reasons for hydronephrosis:

• Idiopathic hydronephrosis that has no obvious cause and usually resolves on its own before or after birth
• Vesicoureteral reflux is when urine does not properly flow from the kidneys to the bladder, but instead abnormally backs up in the ureter (the tube connecting the kidneys to the bladder).
  
• Blockage/obstruction occurring in four possible places:
  • Where the kidney meets the ureter (ureteropelvic junction – UPJ obstruction)
  • Where the ureter meets the bladder (ureterovesical junction – UVJ obstruction)
  • Within the urethra (the tube that carries urine from the bladder out of the body, occurring only in males) (posterior urethral valves – PUV)
  • Incorrect attachment of the ureter to the bladder (ectopic ureter or ureterocele)

Newborns and infants with hydronephrosis usually show few or no symptoms at all. Older children who have moderate to severe cases may experience:

• Pain in the side or abdomen
• Blood in the urine

Rarely, infants and children may be more likely to get urinary tract infections, in which symptoms include:

• Persistent feeling of needing to urinate
• Pain in the lower abdomen during urination
• Cloudy or bloody urine
• Back or side pain
• Fever
• Vomiting

Your child’s hydronephrosis may have been detected before through a routine prenatal ultrasound. In that case, your physician may refer you to our Zickler Family Prenatal Pediatrics Institute for a high-resolution (level II) ultrasound and MRI scans to evaluate your baby’s condition. The Zickler Family Prenatal Pediatrics Institute at Children’s National Hospital may recommend further testing after your baby is born. Read more about the high-risk prenatal care services at the Prenatal Pediatrics Institute.

Alternatively, your child may be referred after birth to one of our urologists to evaluate hydronephrosis that was discovered before birth or after a UTI.

Regardless of how you are referred for hydronephrosis evaluation, one of our pediatric urologists will decide on the ideal set of X-ray studies to understand your child’s urinary tract better. Those studies may include:

• Renal Bladder Ultrasound
• VCUG
• Mag-3 lasix renal scan

There are four main options for treatment, depending on the severity of hydronephrosis in your baby:

• Close observation for mild or moderate cases, including ultrasounds before and after birth
• Antibiotics after your baby is born to prevent infection, in select cases where infection may be more likely to occur
• Surgery to repair any urinary tract blockage, in more severe cases
• Prenatal surgery to place a drainage tube in your baby’s bladder, in the most severe cases

The urologists and surgeons at our Zickler Family Prenatal Pediatrics Institute have extensive experience in the management of hydronephrosis. We develop plans that ensure continuity of care from the early stages of pregnancy, after birth, and across childhood.